1. Field of the Invention
The present invention relates to a semiconductor device.
2. Description of Related Art
A semiconductor device such as an IGBT (an insulated gate bipolar transistor) and an IPM (an intelligent power module) is provided with a semiconductor module including a semiconductor element, and a cooler. In order to enhance cooling performance, grease for cooling is applied on a surface between the semiconductor module and the cooler. Flatness is varied in this surface. Therefore, from the viewpoint of cooling performance, given contact pressure is required inside the surface in order to arrange the grease evenly inside the surface and also to reduce a thickness of the grease as much as possible.
Therefore, Japanese Patent Application Publication 2007-329167 A (JP 2007-329167 A) stated below describes a structure that includes a spring, and a beam fixed by struts corresponding to a plurality of screws. In this structure, a semiconductor module is pressed against a cooler by holding force applied by the beam using a spring load.
However, in the related art described in JP 2007-329167 A stated above, when the holding force is increased in order to reduce a distance between the semiconductor module and the cooler, the cooler is deformed following the holding force, thus tilting the struts. The tilt of the struts may cause deterioration of cooling performance because given contact pressure is not obtained. As a result, accuracy of dimensions such as accuracy of heights, positions, and so on of the device can be decreased.